[Current role of progesterone therapy in the prevention of spontaneous abortion and in the treatment of threatened abortion].

Progesterone therapy is often used to prevent spontaneous abortion. In this paper the most significant studies on the benefits and risks of this treatment over the last 30 years are analyzed. None of these studies about the effects of progesterone as non-specific therapy in abortion risk and recurrent miscarriage, proved a reduced pregnancy wastage in treated patients compared with patients who received no treatment. The results concerning the use of progesterone in recurrent miscarriage for luteal phase inadequacy are more controversial, but they are still inadequate to encourage progesterone supplementation. To obtain a definitive conclusion about progesterone therapy real effectiveness, it is necessary to carry out randomized double-blind prospected trials. As regards the risks of using progesterone therapy during pregnancy, even if a possible teratologic role has certainly been reduced, it cannot be excluded completely yet. Moreover a high incidence of respiratory problems has been noticed in newborns from patients treated with progesterone, compared with control groups.